Core barrel



Jan. l0, 1950 B. w. sl-:wELL 2,494,363

CORE BARREL l original Filed Deo. 21, 1959 ATTORNEY.

Patented Jan. 10, 1950 UNITED STATES PATENT OFFICE GORE BARREL `BenjaminW. Sewell, Tulsa, Okla., assigner to Standard Oil Development Company, acorporation of Delaware Original application December 21, 1939, SerialNo.

i claims; (o1. .c55-72)' VThis is a division of Serial No. 310,284, led

December 21, 1939, now U. S. Patent 2,374,961 and a continuation-impartof applications Serial No. 242,211, filed November 25., 1938, now U. S.Patent 2,216,962, and Serial No. 269,168, led April 2l, 1939, now U. S.Patent 2,238,609, as to common subject matter therein.

The present invention relates to retractable core barrels formed to bedropped through the drill stem to a seat in a core bit and to take asample of the formation. After a core has'been taken, it may` be sealedunder the pressure of the formation and the core barrel withdrawn,leaving the drill stem and the drill in the lbore hole.

It is an object of the present invention-to provide a pressure corebarrel which may be dropped down the drill stem and which will belatched in place when it is seated.

It is a further object of the present inventionto provide a devicehaving both an outer pressure barrel and an inner barrel so providedwith latches that the inner barrel maybe unlatched and dra-wn within thepressure barrel before the pressure barrel is unlatched from its seat.

Another object oi the present invention is to provide a pressure corebarrel having upper and lower valves Vand arranged so that after it hasbeen latched in place in a drill stein the lower valve may be closedbefore the device 4is unlatched from the drill stem and the upper onemay be closed after it is unlatched from the drill stem. A furtherobject of the present invention is to provide a core barrel which may bedropped down a drill stein and which is locked in place.

VWhen it strikes a seat at the lower end of the drill stem. The deviceis so arranged that, when a conventional type overshot attached to awireline is dropped down the drill stem, it will fasten to aspear-shaped head on the upper end of the core barrel. Apull upwardly onthe wireline will withdraw an inner barrel causing a vvalve in the lowerend of the pressure barrel to close and a contimiedV pullwlll unlatchthe device from the drill stem and then close a valve in the upper endof the pressure barrel, so effectively sealing a core in the barrel atthe pressure of the formation.

Other objects and advantages of the present invention will be apparentfrom the following description taken in conjunction with theaccompanying drawing in which i Fig. l is a cross sectional viewthrougha core drill with a preferred modification of the -device ofvthe-present invention installed` therein;

Fig. 2 is a cross sectional view alone the line Fig. 3 is a fragmentaryview of a lower portion of the device, taken at to the view shown in land with Darts broken away to show details of construction.

Referring to the drawing in detail, numeral I designates a .conventionalcore bit head provided with conventional sn tail cutting edges Z --.2and a central passage 3- The lower portion of the central passage 3 indrill head I has a -smaller diameter than the upper portion and forms aledge Il Within the passage,

Core bit head is held in threaded engagement with the lower end of acollar 5, the upper end of theA collar being provided with threads (notshown) for engagement with a conventional tool joint. The lower end ofthe collar yis provided with a ledge 6 pieroedby central passage 3.vLocated on each side of central passage 3 are smaller passages I 'Iwhich also extend through both ledge 6 and the bit head. Collar 5 isalso provided with circumferential grooves I5 and yI6 located at aproper distance above ledge 6, as will hereafter'loe explained. n

Positioned within collar 5 is the pressure. core barrel. An outercylinder 8 having suicient wall thickness to resist a large pressuredifferential has arranged within it a concentric cylinder 9. The lowerend of cylinder 8 is upset to provide a threaded shoulder Ill to whichis attached cylindrical sleeve I l, which has .an inwardly projectingshoulder I2 at its lower end. Sleeve AII is provided with inwardlyprojecting stub shafts I3--I3- Mountedon the stub shafts for rotation'within the space defined by shoulders In and I2 and the interior ofsleeve II is a steel ball I4. Steel ball I4 is provided with atransverse circular opening adapted to receive inner cylinder 9.Shoulders I9 and VI2 are suitably cut away to conform with the shape ofsteel ball I4 and, in

addition, shoulder Ill is recessed just above the cut-away portion toreceive a packing ring I'I which is of vsuch configuration as to form afluidti'ght seal with surface of the ball.

Stub shafts I 3-I3 carry springs I 8-I 8 and are provided with stops 29which cooperate with projecting studsv I9 carried by steel ball I4 tolimit the angular Vmotion of said ball to 90. The upper end of cylinder8 is provided with screw threads and attached thereto by mating threadsis a. cylindrical block 2|. Block-2| is in the form of a cylinder withoutside portions of its upper end milled away to leave a circularshoulder 22 having ribs 23-23 joined thereto. Shoulder 22 screwed to theupper end of bolt 42. -upper face f cap 46 is arranged a disk ofresilient is provided with a central passage 25 and has itsunder-portion bevelled for reasons which will later appear. A passage 26of smaller diameter than the interior of cylinder 8 extendslongitudinally from the lower end of block 2| to the cut-away portionsthereof and has a knife edge 2`| formed onV the lower end thereof.Attached to ribs 23-23 by means of rivets 28-28 are dogs 29-29. Thecylindrical block 2| is also provided with laterally olfset longitudinalpassage 30 controlled by a needle valve 3| and when opened makingconnection with a lateral passage 32 provided with a plug 33 for thepurpose hereafter specified. Access to needle valve 3| is provided by aslot 35 milled in block 2|.

Positioned within the pressure barrel is inner cylinder 9 provided atits lower end with a core catcher 34 and having a cylindrical valve head36 attached to its other end by means of suitable screw threads. Thevalve head is provided around its circumference with slots 3l belowwhich is arranged a seat 38 for a ball valve 39. The upper end of thevalve head is provided with a recess in which thrust bearings 4| arearranged. A bolt 42 has its head 43 resting on thrust bearings 4|, thebolt being held in place by a screw cap 44 carried by the upper end ofthe valve head. A stud 45 is screwed into cap 46 which, in turn, is Uponthe material 4l which is of such dimensions as to form a seat for theknife edge 2l attached to the lower face of cylindrical block 2|.

The stud 45 is screwed into a cylindrical block 48. rhe central portionof block 48 is provided with a slot 49 and attached within slot 48 byrivets 50-58 are dogs 5|-5|. Block 48 is also provided with laterallyprojecting pin 52. Fitting slidingly over block 48 is a sleeve 53provided with a spear head 54 and lhaving its center portionprovidedwith slots 55-55 and 5656. Slots 55 are so arranged that theupper ends of dogs may extend outwardly through them when sleeve 53v isresting in its lowerrnost position in which the upper ends of slots 56rest on pin 52.

An outer sleeve 51 fits slidingly over cylindrical block 2|. The upperend of sleeve 5l is provided with pins 58-58 which project into theslots .E5-55 of sleeve 53. Sleeve 51 is additionally provided with slotsssi-59 placed so that the upper F ends of dogs 25E-29 may extendoutwardly through them when sleeve 5l is resting upon cylindrical block`2| in its lowerrnost position.

The above described device may briey be said to comprise a heavypressure barrel provided with valves at its upper and lower ends and aninner barrel slidingly arranged within the pressure barrel. When thedevice is ready for taking a core, locking means lock the inner barrelagainst longitudinal movement with respect to the pressure barrel, itslower end protruding from the lower end of the pressure barrel and otherlocking means, in turn, lock the pressure barrel in the lower end of thedrill stem provided with a core bit. The lower end of said inner barrelprojects into the head of the core bit in order to receive a core. Whena core has been received by the inner barrel, a pull on the upper end ofthe device unlocks said inner barrel and retracts it within the pressurebarrel to allow the valve in .the lower end ofthe pressure barrel toclose. A continued pull on the upper end of the device next-unlocks thepressure barrel from the drill Vstem and then closes the valve in theupper end of the pressure barrel to hermetically seal the core withinthe pressure barrel.

The device is prepared for taking a core by having the longitudinal axisof the opening in steel ball |4 in line with the longitudinal axis ofouter cylinder 8, the lower end of cylinder 9 being extended through theopening in steel ball I4 and then projected a predetermined distancebeyond it. It will be apparent that cylinder 9 is the sole means foropposing the rotative force applied to the ball by springs |8| 8 andhence for retaining the opening in the steel ball in line with the axisof cylinder 8. In the upper end of the device, upper ends of dogs 29-29and 5 |-5I are momentarily retained inwardly in order to allow sleeves53 and 5'| to assume their lowermost positions, and are afterwardsallowed to fall outwardly. When this occurs, relative longitudinalmovement between cylinders 8 and 9 will be prevented because cylinder 8is attached to block 2| While cylinder 9 is attached to block 48 throughstud 45, and since block 48 rests on a face of block 2| it cannot movedownwardly and upward movement is prevented by dogs 5|-5l restingagainst that part of block 2| which .forms shoulder 22.

With the inner and outer barrels locked together as described in thepreceding paragraph, the device is ready to be lowered into a drill stemin order to take a core. A drill stem having at its lower end a collarand core bit head as shown in Fig. 1 may be in position in a bore holewith the cutting edges of the bit at the point in the hole at which itis desired to obtain a core. The core barrel may then be placed withinthe drill stem and allowed to fall under the force of gravity. If thereis no obstruction within the drill stem, shoulder l2 will strike theledge 6 of the collar and the device will then be locked in thisposition by dogs 29-29 which fall outwardly and engage notch i5, asshown in Fig. l. If there is a" small obstruction between ledge andshoulder |2, shoulder l2 will rest on this obstruction and the devicewill be locked in position by engaging notch I6. In either event thelower end of cylinder 9 will project within passage 3 for the purpose ofreceiving a core. After the device has been locked in place, the drillstem may be rotated and drilling duid forced down the drill stem and outthrough passages 1-7 into the bore hole in the conventional manner. Asthe drill stem rotates, cutting edges 2-2 will cut a core which enterscentral passage 2 and hence cylinder 9.

It will be evident that the rotary movement ci inner cylinder 9 will beindependent of the rotary movement of the drill stem and the outercylinder 8 because cylinder 9 is connected to these other membersthrough the thrust bearings 4|. As the core enters cylinder 9, drillingfluid will be displaced upwardly through ball valve 39 and oui throughslots 3l.

When a core of the desired length has been cui by the bit, the rotationof the drill stem may be stopped and an overshot attached to a wire linedropped down through the drill stem and allowed to engage with spearhead 54. Since such overshots are conventional to the art, this deviceir itself forms no part of the present invention and hence, is notillustrated in the drawing. An upward pull on the wire line attached tothe overshot lifts sleeve 53 until the lower portions o:

Aslots 55 strike dogs 5|, pulling them inwardly thereby unlockingcylinder 8 with respect to cylinder 9. A continued pull upwardly onsleeve 5l causes pins 52 to rest on the lower ends of slot 56,transmitting the pull to stud 45 which retracts cylinder 9 within steelball I4 and allows springs |8-l8 to rotate the steel ball to 90 to closeoff the lower end of cylinder 8. Continuing the pull on sleeve 53 causesthe bottoms of slots 55 to strike pins 58 and pull sleeve 51 upwardly todisengage dogs 29 from notch l5. All the pull is now transmitteddirectly through block 48 to stud 45 which causes disk 41 to seatagainst knife edge 21, sealing off the upper end of cylinder 8 andallowing the force to be transmitted to cylinder 8 in order to withdrawthe entire device from the bore hole.

When the device is withdrawn to the surface of the earth with a coreunder formation pressure in barrel 8, the gaseous components of thesample may be collected by removing plug 33 from block 2l and attachinga conduit from passage 33 to a suitable device for containing thesecomponents. Needle valve 2l may next be opened to allow the gaseousconstituents to be withdrawn from the core barrel to the samplecontainer, thereby relieving the pressure in the core barrel. The corebarrel may then be dismounted to obtain the core and the core barrelthen reassembled and arranged to take another core in the mannerpreviously described.

While I have disclosed ya specic modification of the present inventionit is obvious that various changes in the shape, size and arrangement ofthe parts may be made Without departing from the scope of the invention.For example, the number and shape of the locking dogs used in the devicemay be altered, other means may be used for withdrawing the gaseousconstituents from the sample chamber and other types of core bits may beused. I therefore do not intend to be limited to the above describedmodicaticn.

I claim:

1. A pressure retaining coring assembly to recover a core on the surfaceof the ground at thesame pressure the core left the formation,comprising a string of drill tubing, a core barrel adapted to be loweredinto and raised completely out of the string of drill tubing duringnormal drilling operations, a bit having a passage in the center thereofattached to the end of the drill tubing to cut a core, the core when cutpassing upwardly through the passage in the bit and into the lower endof the core barrel, a valve means arranged adjacent the lower end of thecore barrel adapted when open to pass said core barrel and when closedto seal the lower end of said core barrel, said core barrel passingthrough said valve during the coring operation, and means carried bysaid core barrel for breaking off the core below said valve at the endof said coring operation.

2. A pressure retaining coring assembly to recover a core on the surfaceof the ground at the same pressure the core left the formationcornprising a string of drill tubing, a core barrel adapted to belowered into and raised completely out of the string of drill tubingduring normal drilling operations, a bit having a passage in the centerthereof attached to the end of the drill tubing to cut a core, the corewhen cut passing upwardly through the passage in the bit and into thelower end of the core barrel, a rotatable valve arranged adjacent thelower end of the core barrel adapted when open to pass said core barreland when closed to seal the lower end of said core barrel, said corebarrel passing through said valve during the coring operation and meanscarried by said core barrel for breaking off the core below said valveat the end of said coring opera- `ing to its lower end, a seat on thelower end of the drill tubing to support the casing member when the corebarrel assembly is in core-taking position, a bit having a passage inthe center thereof attached to the end of the drill tubing to cut thecore, a rst valve means associated with the upper end of the casingmember and adapted to seal the upper end thereof in a duid-tight manner,a second valve means mounted on the lower end of the casing member andarranged for sealing the lower end thereof in a fluid-tight manner, acore barrel slidably mounted in the casing member and arranged to haveits lower end extend below the second valve member into the passage ofthe bit when in core-taking position and to be within the casing memberabove the second valve member when in a retracted position, and corebreakers carried by the core barrel at a point below the second valvemember when the core barrel is in core-taking position.

4. A pressure retaining coring assembly to recover a core on the surfaceof the ground at the same pressure the core left the formation,comprising a string of drill tubing, a core barrel assembly adapted tobe lowered into and raised completely out of the string of drill tubingduring normal drilling operations and including a casing member having acentral passage extending to its lower end, a core barrel slidablymounted in the casing member and arranged to assume a forward positionand a retracted position, a seat on the lower end of the drill tubing tosupport the casing member when the core barrel asn sembly is incore-taking position, a bit having a passage in the center thereofattached to the end of the drill tubing to cut the core, a valve meansassociated with the upper end of the casing member and adapted to sealthe upper end thereof in a huid-tight manner, a rotatable valve mountedon the lower end of the casing member and adapted to pass said corebarrel when the latter is in its forward position and to seal the lowerend of the casing in a uuid-tight manner when the core barrel is in itsretracted position, and core breakers carried by the core barrel at apoint below the rotatable valve when the core barrel is in its forwardposition.

BENJAMIN W. SEWEIL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,108,949 Snyder Feb. 22, 19382,164,598 Thrift July 4, 1939 2,216,962 Sewell Oct. 8, 1940 2,238,609Sewell Apr. 15, 1941 2,374,961 Sewell May 1, 1945

